Electrical relay



April16,1946. f AAHKLAMB 2,398,651

ELEGTRI CAL RELAY Filed NOV. 27, 1942 v d f- Rhodium Patented Apr. 16, 19464 uNrrED STATES PATENT GFFICE `:assetti ELECTRICAL RELAY Anthony H. Lamb, Hillside, N. J., allignor to Weston Electrical lmtrnment Corporation,

Newark, N. J., a corporation of New Jersey Application November 27, 1942, Serial No. 467,158

3 Claims.

the upper pivot of the moving coil. This spring l is very thin in relays of high sensitivityA and consequently can carry only a limited current. Excessive current oxidizes the spring and distorts the convolutions even though the current is not suicient to burn or destroy the spring. 1I

An object of the invention is to provide an instrument type relay that can control current ilow of a magnitude substantially higher than that which may be carried by the spring connec- (Cl. G-110) of the pivot post. The outer end of the spiral spring Il is secured to the outer abutment Il that is supported upon the upper bridge I1 which, in turn, is mounted upon the base l by the studs 'Ihe current supply to the contact arm ii is through the spring Il and its abutments, and

the circuit connection to the outer abutment Il may be through the mounting posts il and bridge I1, or directly to the projecting lug Il' of the abutment. The relatively iixed contacts il of the relay are carried by screws 20 that are threaded into bushings 2i mounted on the hooked arms 22 oi the insulating plate l. A spring washer 2l is arranged between a face of each supporting arm 22 and an associated bushing 2| to lock the contact screw against inadvertent rotation, and the washer has an extension 24 to which a circuit connection may be soldered.

tion to the relay contact. An object is to pro- I0 'The several parts that have been described vide an instrument relay in which the moving system is pivotally supported by jewel bearings, and one of the jewels is metallic and establishes a circuit connection to the relay contact arm may be of any desired design as their particular constructions and relationships are not important features of this invention. I'he drawing illustrates the relay that is described and claimed in through the metal stai! that is seated in the Jewel. Patent N0. 1.866.436, Edward F. Weston; and ref- More specifically, an object is to provide an instrument relay in which the moving system includes a staff that is pivotally supported in a metal rhodium-plated bearing, the staf! and bearing constituting a circuit connection to the relay 3 contact arm.

These and other objects and advantages of the invention will be apparent from the following speciilcation when taken with the accompanying drawing in which:

Fig. 1 is a fragmentary plan view of an instrument type relay embodying the invention; and

Fig. 2 is a fragmentary sectional view through the upper bearing of the moving coil, and with erence is made to that patent for a disclosure of appropriate constructions for the parts of the relay that are not illustrated in the drawing o! this patent.

In accordance with this invention, at least the upper Jewel" bearing and, if desired, the lower jewel bearing for supporting the moving system are metallic and provide a current-conducting connection between the fixed parts of the relay and the moving system. As shown in Fig. 2, the

upper bearing is a screw 25, of brass or other metal oi' good electrical conductivity, that is threaded through the bridge I1 and locked in place by the nut 2l that also serves to secure the a diagram of a part of the relay circuit added to 40 outer spring abutment Il to the bridge. The

the view.

As shown in the drawing, the base i of the relay is of insulating material, preferably a molded plastic, with an integral abutment 2 having a groove 3 for receiving the heads of bolts 4 that 5 secure the core l and the contact-supporting plate t to the inner face oi' the abutment. The coil 'l of the relay moving system is pivotally supported for angular movement in the gaps between the core I and the pole pieces 8 of the permanent 50 concave inner end of the screw 2l has an attached layer 21 of rhodium that is preferably applied by an electroplating process.

The rhodium layer 21 is very hard and permanent, and the finish is very smooth when the rhodium is plated upon the accurately shaped and polished surface oi the screw. The coeillcient of friction with the conventional polished steel stail is of the order ot that obtained with the sapphire Jewels, and the rhodium-surfaced jewel may be substituted for sapphire Jewels in various types of instruments. The new jewel has special ad vantages in electrical relays as current may be conducted to the pointer or contact arm through and the steel pivot .Il that is set into the end the Jewelscrew.

The electrical circuits of the relay, as shown diagrammatically in Fig. 2, include a connection In from' one terminal of a current source, such as a battery 3|, to the outer spring abutment I8, and connections I2, 32' from the other terminal of the current source to the respective contacts i9, Il through loads 33, 33'. According to prior practice, the only conductive path to the contact arm Il was through the spring I5 that established a denite limit for the current that could be handled by the relay. The rhodium plated jewel screw 25, pivot I4 and pivot post i0 provide an additional current conductive path and the current ilow through the relay contacts may therei'ore be increased. The resistance of the spring II may be of the order of up to one ohm, and the resistance of the conductive path through the jewel screw will be no higher. The total current .ow to the contact arm Il divides between the spring I5 and the conductive jewel bearing in a ratio inverse to their respective resistances, and the total current iiow may be increased to a value considerably greater than that which may flow through the spring I5.

It is to be understood that the invention is not limited to the described embodiment, and that various changes may be made in the illustrated construction without departure from the spirit of my invention as set forth in the following claims.

I claim:

1. In an electrical relay of the instrument type, a moving system comprising a coil carrying a pointer for cooperation with a relatively stationary contact. metal pivot stads secured to said coil. a magnet having polar surfaces spaced apart by an air gap, bearings cooperating with said stairs to support said coil i'or angular movement in said gap, one or said stats being electrically connected to said contact arm and the cooperating bearing being a rhodium plated metal bearing, and means for completing an electrical circuit to said contact arm in parallel with the connection provided by said staiI and cooperating rhodium-plated bearing; said means comprising a spiral spring, a iixed abutment in which said rhodium plated contact is mounted and to which the outer end of said spring is secured, and an abutment on said moving system electrically connecting the inner end oi said spring to said contact arm.

2. In an electrical relay, a moving system including af coil carrying a contact arm, a magnet having an interpolar gap, means comprising stairs on said moving system and bearings supporting said coil for angular movement in said gap and means including one of said bearings and its associated staiI forming an electrical circuit connection to said contact arm, the said bearing being a metal screw having a surface of rhodium engaged by the cooperating staii.

3. In an electrical relay, the invention as recited in claim 2, wherein said means includes a spiral spring vconstituting a current-conducting path in parallel with said rhodium-surfaced jewel and cooperating staiI.

ANTHONY H. LAMB. 

